[Qt-interest] QDataStream

[phil prentice]

Sorry!!! I've just realised I writeRawData will work because the code below is 
wrong!!!  i.e.
writeRawData(data.m_testResponseData...
should read
os.writeRawData(data.m_testResponseData...

Sorry its been a long day!!!
Phil

On Thursday 19 August 2010 15:55, phil prentice wrote:
> HI
>   I'm using QDataStream to read and write data.  Part of this data consists
> of a fixed length of bytes and so I thought that I could use the member
> functions writeBytes, readBytes or writeRawData, readRawData for that part.
>
> After performing the write I need the reference to the QDataStream, so I
> presume that rules out me using the function writeRawData() because it does
> not return a reference to QDataStream.  If I could get hold of the updated
> reference after the write then read/writeRawData would be perfect for my
> needs.  After a writeRawData() is there anyway I can get the updated
> reference???  Is it effectively updated anyway, because its effectively a
> pointer?
>
> On the other hand writeBytes would work, but readBytes allocates a buffer
> to read into using new....I have my own buffer and simply want to use it
> direct. So I dont want to use this.
>
> If I do something like this will it work?
>
> QDataStream& operator<<(QDataStream& os,
>                                 const TestResponseDataItem &data) // FRIEND
> {
>   os << qint8(data.m_voltageRange) << qint8(data.m_testSelected)
>         << qint16(data.m_testVoltage) << qint8(data.m_testResistance)
>         << qint16(data.m_testFrequency) << qint8(data.m_testPreChargeMode)
>         << qint16(data.m_testPreChargeTime);
>   // Followed by the test response trace data.
>   writeRawData(data.m_testResponseData,
>                         TestResponseDataItem::testResponseDataByteCount);
>   return os;
> }
>
> Because os is a reference is this valid?
>
> or should I simply loop on the buffer writing the data at a byte at a
> time...probably slow??
>
> Thanks for your help
>
> Phil
>
>
>
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